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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 198566.0, MPI für Astronomie / Publikationen_mpia
Observing the dark matter density profile of isolated galaxies
Authors:Prada, Francisco; Vitvitska, Mayrita; Klypin, Anatoly; Holtzman, Jon A.; Schlegel, David J.; Grebel, Eva K.; Rix, H.-W.; Brinkmann, J.; McKay, T. A.; Csabai, I.
Date of Publication (YYYY-MM-DD):2003
Title of Journal:The Astrophysical Journal
Journal Abbrev.:The Astrophysical Journal
Start Page:260
End Page:271
Review Status:not specified
Audience:Not Specified
Abstract / Description:Using the Sloan Digital Sky Survey (SDSS), we
probe the halo mass distribution by studying the
velocities of satellites orbiting isolated
galaxies. In a subsample that covers 2500
deg2 on the sky, we detect about 3000
satellites with absolute blue magnitudes going
down to MB=-14; most of the
satellites have MB=-16 to -18,
comparable to the magnitudes of M32 and the
Magellanic Clouds. After a careful,
model-independent removal of interlopers, we find
that the line-of-sight velocity dispersion of
satellites declines with distance to the
primary. For an L* galaxy the rms
line-of-sight velocity changes from ~120 km
s-1 at 20 kpc to ~60 km
s-1 at 350 kpc. This decline agrees
remarkably well with theoretical expectations,
as all modern cosmological models predict that
the density of dark matter in the peripheral
parts of galaxies declines as
rho;DM~r-3. Thus, for the
first time we find direct observational evidence
of the density decline predicted by cosmological
models; we also note that this result contradicts
alternative theories of gravity such as modified
Newtonian dynamics (MOND). We also find that the
velocity dispersion of satellites within 100 kpc
scales with the absolute magnitude of the central
galaxy as sigma;~L0.3 this is very
close to the Tully-Fisher relation for normal
spiral galaxies.
Free Keywords:Cosmology: Dark Matter; Galaxies: Dwarf;
; Galaxies: Halos- Galaxies: Kinematics and
; Dynamics; Surveys
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
External Affiliations:K ouml;nigstuhl 17, D-69117 Heidelberg,
Germany.; Centro Astron oacute;mico
Hispano-Alem aacute;n, Apartado 511, E-04080
Almer iacute;a, Spain.; Current address:
Instituto de Astrof iacute;sica de Canarias, Via
Lactea, La Laguna, Tenerife, E-38205 Canary
Islands, Spain; and Isaac Newton Group of
Telescopes, Apartado 321, Santa Cruz de La Palma,
E-38700 Canary Islands, Spain.), AB(Department of
Astronomy, New Mexico State University, Box
30001, Department 4500, Las Cruces, NM 88003.),
AC(Department of Astronomy, New Mexico State
University, Box 30001, Department 4500, Las
Cruces, NM 88003.), AD(Department of Astronomy,
New Mexico State University, Box 30001,
Department 4500, Las Cruces, NM 88003.),
AE(Princeton University Observatory, Peyton Hall,
Princeton, NJ 08544-1001.),
AF(Max-Planck-Institut f uuml;r Astronomie,
K ouml;nigstuhl 17, D-69117 Heidelberg,
Germany.), AG(Max-Planck-Institut f uuml;r
Astronomie, K ouml;nigstuhl 17, D-69117
Heidelberg, Germany.), AH(Apache Point
Observatory, P.O. Box 59, Sunspot, NM 88349.),
AI(Department of Physics, University of Michigan,
500 East University Avenue, Ann Arbor, MI
48109.), AJ(Department of Physics,
E ouml;tv ouml;s University, Budapest, Pf. 32,
H-1518, Hungary.; Department of Physics and
Astronomy, Johns Hopkins University, 3701 San
Martin Drive, Baltimore, MD 21218.)
Identifiers:URL:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bi... [ID No:1]
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